The analysis of the protein spectrum of blood was carried out by electrophoresis in agarose gel in combination with the determination of biochemical parameters in 30 stallions of the Arabian breed, divided into groups according to the indicator of progressive sperm mobility. Group 1 included stallions with progressive mobility (PM) up to the 25th percentile (PM, % <53.35), group 2 - stallions with progressive mobility within the 25-75th percentile (53.35 <PM, % <65.18), and group 3 - stallions with progressive mobility above the 75th percentile (PM, %> 65.18). In the 1st group of stallions, the highest concentrations of α2-globulins and γ-globulins of blood were found. The 3rd group of stallions showed the lowest concentration of glucose and urea.